Morphology of larval antennae and mouthparts of four Indian sand flies (Diptera : Psychodidae) by scanning electron microscopy

The mouthparts and antennae of the fourth-instar larvae of four sand fly sp ecies were studied using scanning electron microscopy. The morphology of th e clypeus, labrum, mandible, maxilla, mentum, and antennae were compared fo r Phlebotomus argentipes Annandale & Brunetti, P. papatasin (Scopoli), Serg entomyia babu babu (Annandale), and S. bailyi (Sinton). Most of structures exhibited species-specific features, particularly the characteristics of th e antennae. P. papatasin larvae had heart-shaped antennae, a long mandible, stout maxilla, and a heavy mentum with large teeth. In contrast, P. argent ipes larvae had dumbbell-shaped antennae and a singular club-shaped labrum. The antennae of S. b. babu were ovoid, whereas those of S. bailyi were ell iptical. The labrum of S. b. babu was lanceolate, whereas that of S, bailyi was rounded and exhibited a small, thick projection with several folds. Th e teeth of the mentum of both Sergentomyia species were shelter than those of the Phlebotomus species. Species-specific differences in the morphology of larval mouthparts and antennae indicate that it may not always be necess ary to rely on adult morphology to identify sympatric phlebotomines.